ar X iv : n uc l - th / 0 30 50 89 v 1 2 9 M ay 2 00 3 Double Decimation and Sliding Vacua in the Nuclear Many - Body System

We propose that effective field theories for nuclei and nuclear matter comprise of " double decimation " : (1) the chiral symmetry decimation (CSD) and (2) Fermi liquid decimation (FLD). The Brown-Rho scaling identified as the parametric dependence intrinsic in the " vector manifestation " of hidden local symmetry theory of Harada and Yamawaki results from the first decimation, i.e., CSD. In a recent work we showed that in matter under conditions of high density or high temperature, dynamically generated hadron masses scaled with a common scale. Namely for low densities and temperatures the masses scaled as m ⋆ /m ≃ [¯ qq ⋆ /¯ qq] 1/2 whereas at higher densities and temperatures as [¯ qq ⋆ /¯ qq]. In the present work we summarize new empirical evidence for Brown-Rho (BR) scaling and discuss in a general way its impact on the nuclear many-body problem. While the double decimation should be carried out, it has been a prevalent practice in nuclear physics community to proceed with the second decimation, assuming density independent masses, without implementing the first, chiral symmetry decimation. We show why most nuclear phenomena can be reproduced by theories using either density-independent, or density-dependent masses, a grand conspiracy of nature that is an aspect that could be tied to the Cheshire-Cat phenomenon in hadron physics. We go through some of the history of the chiral symmetry decimation (CSD) which involves BR scaling, in order to show that historically one had to look at very specific phenomena involving transition matrix elements to see that it is necessary. We identify what is left out in the Fermi liquid decimation (FLD) that does not incorporate the CSD. Experiments such as the dilepton production in relativistic heavy ion reactions, which are specifically designed to observe effects of dropping masses, could exhibit large effects from the reduced masses. However they are compounded with effects that are not directly tied to chiral symmetry. We discuss a recent STAR/RHIC observation where BR scaling can be singled out in a pristine environment.